The extraction of minerals is increasingly being undertaken by multinational corporations in remote areas that are often home to indigenous communities. Under growing regulatory pressures many of these companies have improved their social engagement practices. An additional point of leverage is now available to indigenous communities through shareholder activism to change the corporate behaviour of publicly traded companies. This chapter explores two cases of shareholder activism against oil companies in Ecuador using a ‘boomerang’ model of transnational advocacy networks, initially developed by Keck and Sikkink (1998). We adapt this model by focusing on shareholder activism in a case where there is a history of extraction versus a greenfield development. Our research suggests that, with the assistance of international civil society networks, considerable pressure can be exerted on publicly traded multinational companies. Differences in both the density/strength of the network and the vulnerabilities of targeted companies in terms of their size and resource base can influence the efficacy of such activism. In addition, the efficacy of shareholder activism can be hindered where past environmental harms are involved, or where culpability can be ascribed to past owners. Nevertheless, our research finds shareholder activism to be a promising avenue for indigenous communities for constructive confrontation that may make extractive projects more socially responsible and more acceptable to communities.